Medical examination lamp



1935- H. w. ALEXANDER ET AL MEDI CAL EXAMINATI ON LAMP Original Filed Dec. 2, 1933 frwenlors 170mm W u lswmzder Patented Dec. 31, 1935 PATENT OFFIQ E MEDICAL EXAMINATION LAMP HoraceW. Alexander and Walter E. Met zger,

Columbus, Ohio Application December 2, 1933, Serial No. 700,722 Renewed May 18, 1935 .4 Claims.

The present invention relates to illumination, and more particularly to an improvement in lamps especially formedical diagnostic purposes.

The main andprimary object of this inven- ,5 tion is to provide a new and novel inexpensive lamp for-controlling and projecting a relatively cold but intense beam of light, having an extreme znarrow adjustable divergence, of color discriminating quality, of which the maximum heat rays, such as infra-red, are filtered from the beam and dissipated by radiation within the main body of the lamp housing.

In medical diagnostic andsurgical cavity work it is extremely desirable and important to have 1 .an intense beam of cold light filtered to approximate daylight color quality; that important details, such as: blue veins, red arteries, white nerves and yellow bile ducts may be readily distinguished with the minimum amount of heat energy radiated within the area of operation, and that the surgeons and attendants may perform their duties in comfort without the danger of perspiring within the sterile 'field.

Another object of the invention is to provide a lamp structure wherein is combined *in a novel :manner a parabolic reflector which serves to :make. the device useful within the scope of all lzpracticing ..physicians. It is so designed that by the removal of the door containing the'optical :30.:c0ntro1: system. it automatically becomes a pro- *jectoncap-ableof lighting a relatively wide area. 'Ihe introductionsof a door containing a diffused "color discriminating lens permits'the total re- I'flected light 'flux of the reflector to be utilized as a unit of general light distributing characateristicszsimilar to the so-called flood light, then the device becomes extremely valuable as a light 4 source tobe used in conjunction with the head .mirrorusedbyall physicians and surgeons as a *refiectorto redirect light into the body cavities for .pperation and diagnosis work. Further, the devvice with theabove principle will prove valuable as an emergency source of illumination in case of apowerzfa-ilure when equipped-with an automatic x- 1,.means of changing the current'supply from the high voltage transformed to a direct low voltage :cuirentcsuppliedby a'battery source direct.

:- This invention relates to lampstof the projector .type' and aims to provide a novel construction of suchtlamps which-is of such nature that when energy source, similar in construction to the ordiznary automobile typeof lamp bulb,: or any bulb uhaving ahighly concentrated filament, is carried Ann itheomost'advantageous position within a reflector, namelyrwithaits axis coincident with the axis of the reflector, or nearly so, to thus eliminate the maximum amount of destruction of the reflecting surface by the bulb base and socket, the maximum energy fiux may be permitted to pass through a small aperture in a front enclosing cover. Such a structure thus permits of the use of an ordinary projector, such as a common spot light having a parabolic reflector and employing an automobile type of bulb, in connection with a removable front enclosing cover 10 provided with an aperture, and further fitted with an optical system whereby a beam of narrow and controlled divergence and high intensity may be projected by the utilization of one or more reflected light rays rather than by the use of the ,;;l5 direct emanations from the filament itself Such a beam may be given desired characteristics by the use of screens and. filters, as for example the elimination of heat from a beam to be used for light energy or illumination alone. .20

Others have attempted to utilize the direct emanations from a source of energy through an aperture and optical system, but in such attempts only the emanation from a small portion of the source is available. If a high voltage bulb is used, ;.25 the filament is too large to permit any but the merest fraction of the fiux to pass the aperture. If a low voltage lamp, such as an ordinary automobile bulb, is used and placed in the most advantageous position in the reflector, namely, 130 destroying the least of the reflector surface by having the axis of the bulb coinciding with the axis of the reflector, the position of the V shaped .filament is such that a minimum of its projected area is toward the front of the lamp, thus pro-1:35 viding a minimum of light flux available to pass through-an aperture directly in front of the filament, and approximately on the axis of the reflector. Light rays, however, are projected from points on the reflector in a plane at right angles/ to the longitudinal axis of the lamp bulbyand from other points on the reflector, and these rays may be utilized as light or energy sources by placing the aperture in the path of the reflected rays.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawing, wherein like symbols refer to like or corresponding parts throughout/the several views,

Figure 1 is a vertical axial section taken through a lamp embodying the characteristics of the presentinvention, the support being broken away and the dotted lines showing a second adjustment of the optical system.

Figure 2 is a side elevation, on a reduced scale, of the complete lamp as a portable unit capable of adjustment to control and focus the beam over the desired area or field to be illuminated.

Figure 3 is a fragmentary front elevation of the same, showing the location of the optical system relative to the axis of the lamp body.

Figure 4 is a fragmentary, enlarged rear elevation of the aperture and color filter plate, taken on the section 4-4 of Figure 1.

Figure 5 is a fragmentary sectional view on the line 55 of Figure 4, showing the supporting means for the optical system and adjacent parts, and

Figure 6 is a vertical axial section through a modified form of door or front cover for interchangeable mounting on the lamp body, for use in wide beam projection.

In the following description we shall confine our references to the use of such a lamp structure as a surgical light for illumination purposes, but it is to be understood that any purpose served by the structure described is to be considered a part of our invention, whether light or any other form of radiant energy is emanated.

Referring now to the drawing, l5 designates a hood or casing which may be of any desired configuration, such as hemispherical as shown and which at its front is slightly elongated and enlarged to provide an outwardly facing shoulder II and a supporting flange l2 beyond the shoulder. Through the central back portion of the casing I3 is secured a hollow threaded nipple l3 having an attaching flange l4 held by rivets I5 to the inner side of the casing. The nipple l3 provides a means of attachment for the lamp body to a suitable support, and the latter may embody a portable stand having, as shown in Figure 2, a base IS with a telescoping standard H to the upper end of which is adjustably connected an arm I8. A universal coupling I9 is mounted on the outer end of the arm l8 and has a threaded stud screwing into the nipple l3 of the lamp casing ID for adjustably supporting the same. A suitable handle 20 may be attached to the lower side of the lamp casing ID for quickly swinging the lamp into the desired position.

A parabolic reflector 2| is fitted in the front of the casing l and has a marginal flange seated against the shoulder H and the inner surface of this reflector may be silvered to enhance its reflecting value. A packing ring 22, of cork or other suitable material, is placed against the flange of the reflector and serves to seal a plain glass disc 23 within the flange l2 and against the open front of the reflector 3| to protect the reflecting surface thereof.

The reflector 2| has a co-axial lamp socket 24 at its inner end in which is seated a lamp 25 providing the source of illumination. The lamp is preferably of the automobile type, or any suitable type having a concentrated filament 25 and the lamp 25 is supported with its axis coincident with the axis of the reflector so as to obtain the maximum reflecting capacity of the structure, The Wiring to and the control of the energizing of the lamp 25 may be varied to meet manufacturing and using conditions. One arrangement is shown wherein the lamp 25 is grounded through the socket 24, reflector 2| and casing H] to the ground wire 21 of the electrical cord 28 which may be threaded through the stand as shown. The center contact of the lamp 25 may be connected through the socket 24 in the usual manner with a wire 29 leading to a switch 33 mounted in the bottom of the casing l3 and having a control arm 3! at the outer side of the casing adjacent the handle 23 for easy access. The switch 35 is connected to the other wire 32 of the electrical cord 28. Electrical energy may be supplied from any suitable source suitably controlled to meet the capacity of the lamp 25.

A heat wave intercepting cover 32' is mounted on the front of the lamp body and may be in the form of a cap having a marginal flange detachably engaging over the flange l2 of the lamp casing ID.

A stud 33 projects inwardly from the top of the flange of the cap or cover 32' and engages through a suitably formed opening in the flange A2 of the casing, as shown in Figure 1. The bottom of the cap flange carries a set screw 34 which is threadedly carried by the cap flange and detachably engages through the adjacent portion of the casing flange I2 to removably hold the cap or cover 32 on the lamp.

The cover or cap 32 carries an optical system disposed eccentric and parallel to the axis ofthe parabolic reflector 2| and the lamp 25 so that reflected rays only may pass through the optical system. The optical system has a casing 35 which is enlarged and shouldered as at 36 and seated at its rear end in a correspondingly formed opening through the cover 32'. Preferably this opening is formed near the top of the cover as shown. The formed end of the casing is reduced and split and frictionally receives therein a lens tube 31 in the outer end of which 35 is mounted a double convex lens 33 held in place by a threaded flanged ring 33. The optical system may be adjusted by sliding the lens tube 31 in the casing 35. Within the rear end of the casing 35 is seated an aperture plate 40 having a 40 small axial opening therethrough and provided on its inner side with raised lugs 4i engaging the edge portion of a small color screen 42 covering the aperture through the plate 40.

A recessed retaining plate 43 having a central 45 aperture therethrough is fitted over the rear end of the casing 35 and against the inner side of the cap or cover 32'. Screws 44, Figure 4, pass forwardly through the retaining plate 43, cap 32 and into lugs 45 disposed at opposite sides on the flange or shoulder 36 of the casing 35 to clamp all of the parts together. The color screen 42 engages against the inner wall of the recessed retaining plate 43 and is held in place and holds the aperture plate 45 in place.

The cap or cover 32' together with the optical system may be quickly removed from the front of the lamp by releasing the set screw 34, swinging the lower end of the cover 32' outwardly to escape the bottom of the flange l2, and then raising the cover 32' to free the stud 33 from its socket or opening in the upper part of the flange l2.

The clear glass disc 23 is removably held against the packing ring 22 by a lock ring 23', and this ring may be quickly released from its groove in the flange [2 so that the clear disc 23, the packing ring 22 and the parabolic reflector 2i may be readily removed from the lamp. The wires 29 and 32 may be of any suitable length to facilitate assembling and separation of the parts. Of course in the manufacture of the lamp the casing IE) or other parts may be provided with suitable ventilating openings to dissipate the heat generated when the lamp is in use.

color to facilitate color discrimination within,

the field of light.

In both cases the cap or cover will reflect back into the lamp substantially all of the heat waves emanating from the source of light 25 and reflected from the reflector 2|. Thus, a relatively cool beam of light of the desired character and intensity may be projected from the lamp either as a broad beam for general illumination, or as a spot light adapted to illuminate desired spots, cavities or the like. It' is to be noted that the aperture at the inner end of the optical system need not necessarily be a physical opening but that a generally opaque or translucent disc may be employed having a clear spot of the required size through which the reflected light may freely pass on the axis of the optical system.

Whatis claimed is:-

l. A lamp comprising a body portion having a reflector therein and a source of illumination on the axis of the reflector, a relatively flat flanged cover for said body portion having an opening therein offset with respect to the axis of the reflector adapted to admit passage only of light rays reflected from the reflector in parallel and ofiset relation to the axis of the reflector for projecting a spot light and for intercepting heat waves emitted from the source of illumination, and control means supported by the cover for the opening admitting passage only of certain reflected light rays parallel with the axis of the refleotor.

2. In a lamp, a source of illumination, a parabolic reflector therefor, a relatively flat flanged cover means for the front of the lamp having an opening therethrough, and control means supported by the cover for the opening admitting passage only of certain reflected light rays parallel with the axis of the reflector.

3. In a lamp, a housing, a reflector in the housing, a source of illumination disposed within and on the axis of the reflector, a cap for the housing to confine light rays reflected from the reflector and from the source of illumination, said cap having an opening therein oflset from the axis of the reflector, an optical system casing having a reduced end fltting in the opening of of the cap, an apertured plate in the inner end of the casing, a filter screen carried by the apertured plate to cover the aperture, a casing retaining disc secured to the cap to hold the casing thereto, and a lens tube slidably fitted in the outer end of the casing.

4. In a lamp, a housing, a reflector in the housing, a source of illumination disposed within and on the axis of the reflector, a cap for the housing to confine light rays reflected from the reflector and from the source of illumination, said cap having an opening therein offset from the axis of the reflector, an optical system casing having a reduced end fitting in the opening of the cap, an aperture plate seated in the inner end of the casing and having supporting prongs disposed about the aperture of the plate, a filter screen mounted on said prongs over the aperture, a recessed disc fitting against the inner side of the cap and over the filter screen and aperture plate to hold the same in place, and clamping means between the casing and the recessed disc to bind the same against the opposite sides of the cap.

HORACE W. ALEXANDER. WALTER E. METZGER. 

